A Senate committee on Tuesday will consider a bill that would link approval of the Iran nuclear deal to Iran's sponsorship of terrorism. The Obama administration considers terrorism 'tangential' to the deal.

Secretary of State John Kerry will brief the House and Senate this week on the nuclear deal reached with Iran while President Barack Obama returns from a meeting with Cuban President Raul Castro in Panama.

Washington — Should approval of an international agreement limiting Iran’s nuclear program be linked to Iran’s history of sponsoring terrorism?

That question will move to center stage Tuesday when a Senate committee considers legislation that in essence would add renouncing terrorism to the list of Iran's commitments for the United States to honor a final deal.

The terrorism provision, as it’s called, strikes at the heart of the profound differences between President Obama and Congress over the framework nuclear accord worked out by the US and five other world powers earlier this month. Mr. Obama would leave out such provisions, counting on implementation of the agreement to modify Iran’s behavior over time. But many in Congress see an Iran set free from economic sanctions to pursue even more aggressive activities in the region.

But for others, in particular a large number of Senate Republicans, Iran’s support for terrorism is central to any nuclear deal. For one, the ramifications of recognizing the legitimacy of a nuclear program on the soil of an internationally recognized sponsor of terrorism are too great to ignore. Moreover, Iran has a history of threatening the existence of Israel.

Iran’s connection to terrorism will be just one of the issues discussed Tuesday when the Senate Foreign Relations Committee considers a bill to ensure congressional oversight of any final nuclear deal with Iran. The legislation would give Congress a 60-day review period, during which the president would be barred from lifting any Iran sanctions that were imposed with congressional approval.

The White House opposes any congressional action while international negotiations are in progress, worried legislation now could prompt Iran to walk away from the final negotiations or disrupt the unity of the six powers pressing Iran for a deal by June.

But administration officials are particularly worried about the inclusion of what they consider to be “tangential” issues – like Iran’s support for terrorism – that they suspect have more to do with killing a nuclear deal than strengthening it. Specifically, Tuesday's bill would require the administration to periodically certify that Iran had not engaged in terrorism against the US – or if it had, US sanctions would snap back into place.

Backers of the framework deal have taken to calling such provisions “poison pills” aimed at ensuring that Iran rejects reaching a final accord.

The legislation’s terrorism provision “introduces an issue utterly unrelated to a nuclear agreement,” says Edward Levine, a member of the Center for Arms Control and Non-Proliferation’s advisory board. “It sends the message that even if Iran complies fully with a nuclear agreement,” he adds, “the United States may decide not to meet its own obligations under the agreement.”

Mr. Levine, a former senior staff member on the Senate Foreign Relations Committee, says the terrorism provision is only one of several “poison pills” in the bill, sponsored by committee chairman Bob Corker (R) of Tennessee and Sen. Robert Menendez (D) of New Jersey.

While attracting considerable Democratic support, the bill was still thought to be several votes short of the 67 votes that would be required to overcome a presidential veto.

Democrats supporting the legislation are considering amendments that might help attract more Democrats. Some of those changes would modify or eliminate measures such as the terrorism provision. But some Republicans are considering proposing amendments that would add new “non-nuclear” requirements for congressional approval of a deal, such as insisting that Iran first recognize Israel’s right to exist.

Administration officials call the last-minute addition of such non-nuclear requirements “moving the goal posts.” For some critics, on the other hand, Obama’s refusal to use the nuclear deal to pressure Iran on issues like terrorism underscores how little he is willing to demand of Iran to get a deal.

For Obama, the goal is to secure a deal that limits Iran’s nuclear program and then expect the years of implementation to modify Iran’s behavior as it rejoins the international community. As the Iranian economy “becomes more integrated with the world economy … in many ways it makes it harder for them to engage in behaviors that are contrary to international norms,” Obama said in an NPR interview last week.

With many in Congress taking the opposite view – that a healthier economy will only embolden Iran – removal of the terrorism provision from nuclear legislation seems likely to face a hard sell.